Fuel supply system and valve therefor



c. A. PARSONS 41,933,753

FUEL SUPPLY SYSTEM AND VALVE THEREFOR Nov. 7, 1933.

Filed Dec. 31, 1931 2 Sheets-Sheet 1 IN VEN TOR.

V 'YW W,

ATTORNEYS 1933- c. A. PARSONS FUEL SUPPLY SYSTEM AND VALVE THEREFORFiled Dec. 31, 1931 2 Sheets-Sheet 2 fa... {I 1w w W W M M W? A TTORNEYSPatented Nov. 7, 1933 UNITED STATES PATENT OFFICE FUEL SUPPLY SYSTEM ANDVALVE THEREFOR Application December 31, 1931 Serial No. 584,087

9 Claims.

This invention relates to a force feed fuel supplying system for motorvehicles and a by-pass valve therefor.

The main object of the invention is to provide in a system of thischaracter valve means whereby the pump will be able to supply fuel tothe carbureter from the supply tank on the vehicle at asubstantiallypre-determined and constant pressure regardless of thepositive or negative 10 head to which the system is subjected as thesupply tank is raised or lowered by the vehicle above or below thecarbureter in the travel of the vehicle over a roadway. By thisarrangement, the system will not siphon through the return or by-passline to de-prime the pump when the-vehicle is ascending a grade nor willthe carbureter be flooded when vehicle is descending a grade. In

either case, the pump will function properly to supply fuel to thecarbureter at the pressure de- 0 sired regardless of the position of thesupply tank above or below the carbureter except for the time thepositive head on the system from an elevated tank becomes greater thanthat for which the valve is set. The system and valve means of myinvention are especially adaptable to motor trucks, buses and the like,where the fuel tank at the rear of the vehicle is usually at aconsiderable distance from the carbureter at the front of the vehicle byreason of the long length of vehicles of this character. Due to thedistance apart of these devices, a considerable positive or negativehead is created on the system when the vehicle is descending orascending a relatively steep grade by reason of the distance that thesupply tank is lowered or raised by the vehicle with respect to thecarbureter. With my invention these head conditions do not aifect theoperation of the pump and the latter supplies fuel to the carbureter ata substantially pre-determined pressure at all times.

In carrying out the objects of my invention, the valve device in thereturn line of the system is so constructed and designed that it may beset to determine the pressure at which the pump delivers fuel to thecarbureter from the supply tank. A negative head on the system by thelowering of the supply tank will not open the valve and thus the systemcannot siphon back to the tank. A positive head on the valve as producedby raising the tank will not open the valve except when the elevation ofthe tank is to such a point as to create a positive head in excess ofpressure for which the valve .is set. Under this condition, which isusually the extreme, the pump is required to pump against whateverpressure is at the rear of the vehicle.

developed by the positive head when it that at which the valve is set.

In the accompanying drawings:-

Fig. 1 is a diagrammatic view showing a system of the character referredto equipped with a valve device of my invention;

Fig. 2 is a similar view showing the system in reversely inclinedpositions to be hereinafter described;

Fig. 3 is a vertical sectional view of the valve 5 device; and I Fig. 4is an elevational view of the same.

In the drawings, 1 indicates the fuel supply tank 2 indicates thecarbureter at the front of the vehicle. 3 indicates the intake manifoldconnected with the carbureter as in assemblies of this character. 4indicates a force pump, as of the rotary type, driven from the vehicleengine, and connected with the tank and carbureter, respectively, forsupplying fuel to the latter from the tank at a predetermined positivepressure, as for example, four pounds. A pipe line 5 connects the tankwith the pump on its intake side, while a pipe line 6 connects thecarbureter with the pump on its discharge side, as shown in Figs. 1 and2. A bypass or return line 7 connects the pump on its discharge sidewith the tank through a T-fitting 8 joining pipe lines 6 and 7, asshown. A strainer 9 is in the supply line 5. A valve device 10 of myinvention is in the return line 7.

Valve device 10, as shown in Figs. 3 and 4, comprises a casing 11 madewith its opposite ends open and closed by screw caps 12, 13. These capsclamp flexible diaphragms 14, 15 in the casing on seats providedtherefor at the sides of the a casing. Gaskets may be employed at theedges of the diaphragms to prevent leakage past the same. The diaphragmsextend across the casing in opposed relation and the space between thediaphragms is divided into two chambers 16, 17, one for each diaphragm,by a partition structure arranged within the casing. This partitionstructure comprises horizontal webs 18, 19, one adjacent each diaphragmand a vertical web 20 extending between the horizontal webs and formingtherewith seats for valve members 21, 22 carried by the respectivediaphragms on the inner sides of .the same. The valve members 21, 22 aresecured to their respective diaphragms by fastenit) exceeds ing members23, 24, which may be in the form of screws engaged with nuts 25, 26 onthe outer sides of the diaphragms. The nuts are of such size and shapeas to support coiled springs 27, 28,

one for each diaphragm and lying between the 15 on the outer sides ofthe diaphragms to the atmosphere. The caps have threaded elements 12 13'by means of which the tension of the springs '27, 28 may be adjusted tohold the valves 21, 22 closed at the same or substantially the samepressure as required by my invention. The elements 12 13 are preferablyin the form of screws extending into the caps through their end wallsand engaging discs or plates 12 13 forming movable abutments for theouter ends of the adjacent springs 27, 28. Each screw has its outer endso formed that it may be engaged for turning, and a lock nut 12, 13 isprovided for holding the screw in its adjusted position.

In accordance with my invention, and as shown in Fig. 3, the valvedevice is so made that the areas of the diaphragms 14, 15 as exposed totheir respective chambers 16, 17 are exactly the same, and the same istrue of the valve members 21, 22. In short, the diaphragms and theirrespective parts are duplicates ofeach other, so

that the valve device is a balanced one regardless as connected with thedischarge side of the pump,

and the chamber 1'7 as connected with the tank 1.

The pressure at which the pump 4 delivers fuel to the carbureter fromthe tank 1 will depend on the pressure at which the springs 27, 28 areset to close their valves 21, 22. Under ordinary conditions, thesesprings are set to exert a four pound pressure on their valves, and thepump 4 will deliver fuel at this pressure to the carbureter in theoperation of the system. In case an excess pressure is created by thepump, such pressure will act through chamber 16 on diaphragm 15 and openvalve 22, thus relieving the pressure through chamber -17 and returnline 7. Although valve member 21 of the other diaphragm 14 is subjectedto this excess pressure in chamber 16, said valve will not be opened dueto the larger pressure. area presented by diaphragm 15. I

The delivery of the pump 4 to the carbureter 2 at a predeterminedpressure is in no way affected when the vehicle equipped with the hereindescribed fuel supply system is traveling or standing on a level orsubstantially level roadway. At this time, the parts of the systemoccupy the positions shown in Fig. 1. It is only when the vehicleascends or descends a grade, and more particularly a relatively steepgrade, that the discharge of the pump at a predetermined pressure wouldbe affected, if it were not for the use in the return line :7 of thevalve device 10 of my invention. 1

When the vehicle ascends a steep grade, the parts of the system occupythe positions shown in full lines in Fig. 2. Under this situation thetank 1 is lowered considerably below the carbureter and presents acondition for the pump to siphon back to the tank 1 through the returnline '7. This, however, is prevented by the valve device 10, due to thefact that both valves 21, 22;

are held by their springs against their seats, and the portion of thereturn line 7 connected with the discharge side of the pump is closed tothe portion connected to the tank 1. As valve 22 will not open exceptunder an excess of pressure at which the pump discharges to thecarbureter, the pump will maintain that pressure regardless of thelowering of the tank 1 below the carbureter. The negative head soprovided by lowering the tank will not open valve 21, and when valve 22is opened by excess pressure created by the pump, the system will notsiphon back to the tank.

When the vehicle is descending a grade, the parts of the system assumethe positions shown in dot and dash lines in Fig. 2. At this time thetank 1 is raised above the carbureter andcreates apositive head againstdiaphragm 14 through chamber 17. If this head is in excess of theclosing pressure of the spring on the diaphragm, the latter W21 beraised and valve 21 will open admitting t e pressure into chamber 16 andopening valve 22. As the pressure surfaces of both diaphragms are equal,the pressure of the positive head thereon will be equalized, and thepump will be required merely to pump against this excess pressure. Underthe most extreme conditions of road grade and distance of the tank 1from the carbureter 2, this is not excessive, and with my valve devicein the return line, flooding of the carbureter is prevented when thetank is elevated to create a positive head on the system in excess ofthat for which the valves are set.

With the valve device of my invention incorporated in the return line ofthe system, the pump will have its full suction qualities and capacitiesat all times and will be able to maintain a substantially predeterminedand constant pressure on its discharge side, regardless of the change inelevation of the supply tank 1 by the vehicle with respect to thecarbureter as the vehicle travels, over a roadway. In thedrawings, thesupply tank 1 is shown relatively small in diameter as compared to thepump 4 and other elements of the system. This-is made necessary byreason of the small scale of the diagrammatic views of Figs. 1 and 2. Inpractice the tank 2 is relatively large so as to hold the requiredamount of fuel for the engine with which the system is used.

The details of construction and arrangement of parts shown and describedmay be variously changed and modified without departing from the spiritand scope of my invention, except as pointed' out in the appendedclaims.

I claim as my invention;

1. In a force feed fuel supplying system for motor vehicles, a fuelsupply tank and a carbureter arranged on the vehicle adjacent theopposite ends of the same, a pump connected on its intake side with thetank for drawing fuel therefrom and on its discharge side with thecarbureter for supply fuel thereto, a return line connecting thedischarge side of the pump with the tank for by-passing fuel about thecarbureter, and valve means in the return line causing the pump todeliver fuel to the carbureter at a pre-determined pressure regardlessof the change in position of the tank by the; vehicle above or below thecarbureter in the travel of the vehicle'over. a roadway.

2. In a force feed fuel supplying system for motor vehicles, afuelsupply tank and a carbureter arranged on the vehicle adjacent theopposite ends of the same, a pump having its intake side connected withthe tank for drawing fuel therefrom and its discharge side connectedwith the carbureter for supplying fuel thereto, a return line connectingthe discharge side of the pump with the tank for by-passing fuel aboutthe carbureter, and valve means in the return line causing the pump todeliver fuel to the carbureter at a predetermined pressure regardless ofthe head produced on the valve means from the tank in the raising orlowering of the same by the vehicle above or below the carbureter in thetravel of the vehicle over a roadway.

3. In a force feed supplying system for motor vehicles, a fuel supplytank and a carbureter arranged on the vehicle adjacent the opposite endsof the same, a pump having its intake side connected with the tank fordrawing fuel therefrom and its discharge side connected with thecarbureter for supplying fuel thereto, a return line connecting thedischarge side of the pump with the supply tank for by-passing fuelabout the carbureter, andvalve means in the return line causing the pumpto deliver fuel to the carbureter at a pre-determined pressure whetherthe vehicle is on a level roadway or ascending or descending a grade.

4. In a force feed fuel supplying system for motor vehicles, a fuelsupply tank and a carbureter, a'pump having its intake side connectedwith the tank for drawing fuel therefrom and its discharge sideconnected with the carbureter for supplying fuel thereto, a return lineconnecting motor vehicles, a fuel supply tank and a carbureter, a pumphaving its intake side connected with the tank for drawing fueltherefrom and its discharge side connected with the carbureter forsupplying fuel thereto, a return line connecting the discharge side ofthe pump with the tank for by-passing fuel about the carbureter,

and avalve device in the return line, said valve device having valvesand movable pressure receiving members for normally closing the valves,one member being subject to the pressure created by the pump forcontrolling the pressure at which the pump delivers fuel to thecarbureter, and the other member being subject to the pressure conditionin the return line between the valve device and the tank, said membershaving substantially equal areas exposed to their respective pressures.

6. In a force feed fuel supplying system for motor vehicles, a fuelsupply tank and a carbureter, a pump having its intake side connectedwith the tank for drawing fuel therefrom and its discharge sideconnected with the carbureter for supplying fuel thereto, and a valvedevice for controlling the by-passing of fuel from the pump to the tankabout the carbureter, said valve device having two chambers, oneconnected with the discharge side of the pump and the other connectedwith the tank, a pair of ports connecting said chambers, and a valvemember and a flexible diaphragm therefor in each chamber for normallyholding the valve member in close relation to its associated port.

7. In a force feed fuel supplying system for motor vehicles, a fuelsupply tank and a carbureter, a pump having its intake side connectedwith the tank for drawing fuel therefrom and its discharge sideconnected with the carbureter for supplying fuel thereto, and a, valvedevice for controlling the by-passing of fuel from the pump to the tankabout the carbureter, said valve device having two chambers,oneconnected with the discharge side of the pump and the other connectedwith the tank, a pair of ports connecting said chambers, a valve memberand a flexible diaphragm therefor in each chamber, and pressure meansacting on the diaphragms for normally closing the valve members againsttheir respective ports.

8. In a force feed fuel supplying system for motor vehicles, a fuelsupply tank and a'carbureter, a pump having its intake side connectedwith the tank for drawing fuel therefrom and its discharge sideconnected with the carbureter for supplying fuel thereto,- and a valvedevice for controlling the by-passing of fuel from'the pump to the tankabout the carbureter, said valve device having a casing provided withtwo chambers, one being connected with the discharge side of the pumpand the other connected with the tank,

a pair of ports connecting said chambers, a valve member and a flexiblediaphragm therefor in each chamber, spring means acting on thediaphragms for normally closing the valve members against theirrespective ports, and means for adjusting the tension of the springs.

9. In a force feed fuel supplying system for motor vehicles, a fuelsupply tank and a carbureter, a pump having its intake side connectedwith the tank for drawing fuel therefrom and its discharge sideconnected with the carbureter for supplying fuel thereto, and a valvedevice for controlling the by-passing of fuel from the pump to the tankabout the carbureter, said valve device having two chambers, oneconnected with the discharge side of the pump, and the other connectedwith the tank, a pair of ports connecting said chambers, and a valvemember and a movable pressure receiving element therefor in each chamberfor normally closing the valve member against its associated port, thevalve members and pressure elements presenting differential pressureareas to the pressures created in the respective chambers.

CLYDE A. PARSONS.

